The so-called single use support is still used at the present time in many areas of underground mining. It consists primarily of suitably sized wood props, trough profile supports, double-T supports, etc. Often individual hydraulic props are also used, either to supplement the latter or by themselves. This results, however, in great expenditures because of the high production costs. The required support pressure in these hydraulic systems may be maintained advantageously by the pressure in the hydraulic system (300 to 600 bar) and accurately operating pressure limit valves. All props in the system are characterized by identical characteristic lines. Such hydraulic systems represent the optimum technical solution for rock support in a mobile version. But in a stationary version the above mentioned disadvantages occur. In headways where convergence is expected, so-called flexible trough profiles are used, whereby the friction coefficient is inaccurate and thus a safe and even support of the ceiling or the roof cannot be ensured. This also applies to the two-part roadway or headway props known from German Patent 818 332 where the outer prop is filled with a compressible fill mass. The intention there is to achieve a specific flexibility of the otherwise rigid construction. But the disadvantage is that such elements are not tight enough for effective fill masses to be used. The used bitumen-like plastic fill masses however do not provide the necessary and required support pressures. The same is true for the solution known from German Offenlegungsschrift 32 36 421.0 in which such a pasty mass is arranged between two hollow tubes and is supposed to be displaced from there.
The invention thus has the task of creating a support element used as a single use prop which supports early on, absorbs high pressures, and is easy to handle.